New Border re-entry rules. 

All General Aviation Aircraft Entering the United States must advise United States Customs within one hour prior to re-entry of the pilots names, passengers names, and passport information.

Failure to do so is subject to a $5,000.00 fine or more.

 Here is a link to the new regulations:

 http://edocket.access.gpo.gov/2008/pdf/E8-26621.pdf

I don't recommend using the Federal Government eAPIS site, since, if you do you grant unfettered access to all data on your computer, at anytime the goverment wants to access it... in person, or remotely.

Use Duat.com, Duats.com or Fltplan.com's services... at least you'll maintain control over your computer.